The actinomycins are potent inhibitors of RNA synthesis and are effective in the treatment of certain cancers. The goal of this research is to understand from a molecular, thermodynamic, and electronic viewpoint the nature of the actinomycin DNA complex. The interactions of the actinomycins (especially actinomycin D) and a series of deoxydinucleotides and deoxyoligonucleotides will be studied as models for the DNA complexes and compared to DNA binding studies. The nature of the complexes will be characterized by nuclear magnetic resonance, visible, circular dichroism, fluorescence, and fluorescence detected circular dichroism spectroscopies.